BIT 1987 Volume 6 Issue 1

Two experiments are reported which compared proof-reading performance cross
three different modes of presentation. The results of Experiment 1 indicated
that proof-reading accuracy was significantly worse on a VDU than on paper,
with a photograph of the VDU display producing intermediate performance. It
was also demonstrated that substitutions of visually similar errors were harder
to detect than other error types. The results of Experiment 2 replicated these
findings, but failed to find any difference between twin-column and
single-column presentation. The findings are interpreted as indicating that
character font may be a major factor in the poor performance with the VDU. It
is suggested that the present experimental paradigm could be a useful
assessment tool for the evaluation of display design.

On the Limits of Expert Systems and Engineering Models in Process Control

The review is based on an analysis of current literature of expert systems
and of system engineering models in dynamic process control. It starts with an
analysis of the mental operations and cognitive requirements needed for
supervisory control. Mental models are discussed as a function of situational
requirements as well as of personal strategies. System engineering models and
expert systems are briefly described and their function as decision support
tools evaluated. Criteria are the overall functionality, similarity of
knowledge bases and reasoning strategies of the human and the support system,
adaptability to the operator's skill level and self-explanation of the support
system in the interaction mode. As a result, system engineering models are
only of limited value for knowledge-based process control. Expert systems seem
to be very valuable tools for augmenting human decision making in process
control, if the interaction problem can be solved.

This article reviews the literature on behavioural factors in menu retrieval
from computerized databases. The belief that menus are easy to learn and easy
to use is questioned; in laboratory-based experiments error rates were
uniformly high, success rates less than perfect, searches inefficient, and
search times long. General problems with the menu method and possible
cognitive factors contributing to these problems are discussed. This analysis
suggests several approaches for improving menu retrieval performance: optimal
index structuring, reclassification and relabelling of problem menus, the
addition of descriptors on top index levels, and practice. Each was found to
be effective to some degree in improving performance. A major weakness of menu
systems was found to be their unsuitability for experienced users. The
addition of menu keywords to a menu system overcomes this problem: menu
keywords permit users, as they gain in experience, to access directly deeper
and deeper levels in the menu index, substantially improving both preference
and performance. The addition of user-defined keywords appears promising as
another method for improving performance, particularly for experienced users.
The paper concludes with a discussion of recommendations for practitioners as
well as for researchers.

Individual Differences and Ergonomic Factors in Performance on a
Videotex-Type Task

This study manipulated ergonomic aspects of a videotex-type task and
attempted to relate paper and pencil measures of field dependence-independence,
intelligence, capacity to complete a computer science curriculum and attitudes
toward computers, to the performance of novice users. Results indicated that
fault-tolerant aspects of the software and the use of self-defined commands
resulted in superior performance. In addition, field independence and higher
intelligence were associated with better performance. No substantial
relationship was found between ability to complete a computer science
curriculum and performance on the task. Those subjects who expressed an
'awesome' view of the nature of computers appeared to perform less well and it
was suggested that this may be related to this lack of experience, although it
was not possible to statistically verify this interpretation.

BIT 1987 Volume 6 Issue 2

Menu selection systems provide a means of selecting operations and
retrieving information which requires little training and reduces the need for
memorizing complex command sequences. However, a major disadvantage of many
menu selection systems is that experienced users cannot traverse the menu tree
significantly faster than novices. A common solution to this problem is to
provide the menu selection system with a jump-ahead capability.
The purpose of this research was to evaluate two jump-ahead methods
(type-ahead and direct-access). In the type-ahead method the user anticipates
a selection on each of several successive menus and enters as many selections
at one time as desired. In the direct-access method, each menu frame is
assigned a unique name which the user must enter to locate it.
Thirty-two students were given training on an information retrieval system
for college course information and were required to learn the two jump-ahead
methods in a counterbalanced design. The direct-access method resulted in
fewer traversals to learn the system, lower error rates, and reduced learning
time. The subjective impressions, obtained from post-experiment questionnaires
and oral comments, indicated that the direct-access jump-ahead method was also
preferred in a frequently used menu selection system.

A detailed case study is presented of the use of CNC machine tools in an
engineering factory. This examines what choices were made regarding the
management and operation of CNC machines, and why, and the impact of these
choices on the firm and its employees. Contrary to a deskilling hypothesis,
the findings showed that CNC machinists exercised high levels of operational
control, were very skilled, satisfied with the content of their jobs, but
critical of work coordinating mechanisms. These job designs are linked to
internal and external contingencies. The paper concludes with predictions
concerning job designs associated with the move to complex information
technology systems.

Proof-reading on either a cathode ray tube visual display unit (VDU) of
average quality or on conventional paper typescript was carried out for four
50-min sessions, two in each condition. The method of signaling errors in the
script was identical in each case: verbally and by line reference. VDU scripts
were presented in a standard Wordstar format; paper text was a normal print-out
of that script. With the VDU as compared to paper, more proof-reading errors
were missed, fewer pages were read, and there was a greater accumulation of
fatigue during the reading session as indexed by an increase in the number of
errors missed. It is suggested that (i) material be printed for proof-reading,
and (ii) the present technique be used for comparison of different VDUs for
speed and accuracy of reading and resistance to fatigue.

Metaform: Updatable Form Screens and their Application to the Use of Office
Metaphors in Query Language Instruction

A database interface language and system, called Metaform, which
automatically generates multi-relational form screen interfaces for use by
non-computer professionals has been developed. A form screen is a subset of
the relational database, with a particular relation or combination of relations
being represented. Through form screens, users can simultaneously query and
update several relations in the database without having to know about its
underlying structure. An overview of the Metaform system is presented and
several examples of the use of the Metaform query language and update operators
are described.
A series of 'usability' studies were conducted on a prototype of the
Metaform system to examine the claims that the form concept aids computer-naive
users in building complex database queries. These studies adopted the form
screen concept to present six office paper work analogies to users to help them
to understand the database retrieval concepts. The analogies of a file
cabinet, a file folder, a stack of forms, a single form, a table of information
on a form and a field of information were used in a two-staged training module.
At the end of each training sequence, users answered questions with the
prototype and with paper and pencil which tapped their understanding of the
database retrievals they were learning to perform. The results from these
questionnaires were mixed. Users performed successful relational queries for
simple retrievals and for those using existential quantifiers. They had
difficulty with queries involving multiple steps and intermediate stages.
Although users understood and used the analogies, they ran into difficulties
with the ambiguities in the English statements of the queries, thus suggesting
a need for another level of metaphors and/or problem representation tools not
associated with the machine but with the user's comprehension of database
retrieval problems.

To learn to use an interactive system, a person typically has to acquire a
good deal of new knowledge. The ease of learning will depend on the extent to
which the design of the task and the interface capitalizes on the user's
pre-existing knowledge and his or her cognitive capabilities for learning.
This paper explores the nature of both design decisions and user learning with
a command-based system. Three studies were conducted, all involving a task in
which secret messages were decoded by means of a sequence of commands (based on
the task used by Barnard et al. 1981). In Study I, software specialists
designed command structures for the task and gave reasons for their choices.
In Study II, naive subjects chose between alternative command terms. In Study
III, subjects learned to use interactive versions of the task in which dialogue
factors (command terms and argument structures) were systematically varied.
The results enabled the development of user knowledge of the system to be
specified in detail. Comparisons across the three studies highlighted the
diversity of the factors determining both design decisions and user behaviour.

Traditional data processing methods of implementing systems have led to many
human problems and have often not been successful. This paper reviews a number
of alternative design methods, both centralized methods such as structured
design methods, and decentralized or end user-developed systems. It concludes
that, whilst the new methods are all more user-centred in concept, they may
still fail because the methods necessary to deal with user issues are not
widely available. The paper ends by reviewing the required methods which
include task analysis, prototype evaluation, interface design and continued
user support. Some examples of the required methods are provided.

There are millions of workers worldwide who use video display terminals
(VDTs) on a daily basis. Over the past decade VDT users have reported a
variety of health complaints that have been associated with VDTs including
visual and musculoskeletal discomfort and psychological distress. In addition
VDT users have expressed fears about radiation from VDTs and more recently
concerns about adverse reproductive effects. This paper explores the potential
health effects of working at a VDT based on an evaluation of current research
literature and indicates where more research is underway or needed to better
define health risks. Some conclusions about the seriousness of potential
health effects are presented.

In order to avoid musculoskeletal problems when working at a VDT terminal,
biomechanical aspects of sitting and of working in a sedentary position need to
be considered. This paper reviews relevant biomechanical knowledge and relates
it to field studies of VDT users and their preferred workstation settings. It
is concluded that even though good agreement exists between subject comfort
rating and preferred postures on the one hand and biomechanical data on the
other, an ergonomic work organization is necessary to achieve the best possible
work conditions.

This paper provides an overview of software ergonomics in human-computer
interface design, with a particular emphasis on the pre-requisites concerning
user and task analysis. It is stressed that a consistent ergonomical analysis
has to be carried out following a top-down approach, and not as a checklist of
ingredients in cookery book recipes. Several criteria and critical issues are
discussed regarding the design process itself, the dialogue and alternative
input/output devices. Dialogues using synthesized voice and human voice
recognition are discussed. The ergonomics of programming is briefly mentioned.

To determine if there was an economic justification for purchasing new,
task-oriented and ergonomically-suitable workstations for an office in which
automation was being introduced, a study was designed which examined the effect
of a more comfortable and functional office setting on employee satisfaction
and productivity. This study was conducted at a United States Government
installation. Through task analysis questionnaires and interviews, workstation
and layout requirements were defined for an organization of procurement agents
and support staff. These personnel were to receive computers at their
workstations -- one terminal for every two people. Designs for typical
workstations were created as well as a layout for two typical workgroups of 17
employees. The workstations and layout were implemented using two different
types of furniture: one work group received Systems Furniture, while the other
received additional pieces of their existing Conventional Furniture
(Improved-Conventional). Four work groups within the same division served as
the Control (received no environmental manipulation). Archival performance
data consisting of workhours and the number of line items produced was
formulated into a productivity ratio. Productivity of each group, as well as
satisfaction ratings, were gathered before and after the application of the
improved workstations. The results of the study supported the hypothesis that
improvements to the workstations would significantly, and positively, impact
both productivity and satisfaction. The Systems Furniture group demonstrated a
significant increase in both productivity (20.6%) and satisfaction after moving
into the new workstations, while the Improved-Conventional group showed a
non-significant increase (4%) in productivity but a significant increase in
workstation satisfaction. The control group did not significantly change on
either measure. It can be concluded from this and other studies that
satisfying office requirements can improve both productivity and employee
satisfaction. This result can be translated into economic terms. The cost of
providing the Systems workstations was amortized, due to space saving and
increases in productivity, in only 10.8 months.

Toshiba House Reorganization: The Pragmatic Use of Space in an Existing
Industrial Building

The present communication structures of many organizations are governed by
extensive manual information transfer, long processing times and receptive
recording of data. The introduction of computer-integrated manufacturing (CIM)
has the aim of integrating administrative data in manufacturing data, that is
to say, the operational EDP-systems of all company sections will be -- as far
as possible -- cross-linked. Existing data can be used by all departments of
the company for administrative operations, due the cross-linkage of data
transfer. In this way, recording and processing errors will be avoided or
minimized. Transition from information processing to professional (expert)
systems requires new and more efficient forms of an employee-oriented work
organization.

A product that is adapted individually to a specific market segment, that is
innovative, and that is constructed aesthetically, will be successful. In this
process there is a triangular relationship between designer, client, company
and market, where functional communication has to be ensured. Globally the
market has segmented into age groups, so that aesthetic attitudes are
independent of nationality. Design should distinguish a product from the mass
by accentuating its individual characteristics and so enable the consumer to
identify with it. Today's design determines tomorrow's quality of life. This
article describes the process of product development as exampled by the Wenger
1/1 Office Printer.
The design development procedure is divided into three phases: (a) planning
phase; (b) project phase; (c) realization phase. The printer market is
described, and the most important product requirements defined. The design
concept was that a product should be developed that combined the advantages of
impact- and non-impact printing techniques with a new, market-influencing
design. There were two options with regard to the Wenger 1/1; (a) mechanical
and electronic parts combined in one housing; (b) mechanical and electronic
parts in separate housings. In order to ensure optimal noise silencing, option
(b) was chosen. The favored option was realized in a foam-rubber model, and
details worked out. A 'function-model' was manufactured and tested to ensure
performance and market-adjustment of the new product. The designer and the
client then liaised to supervise the product through to serial manufacture.

The design of keyboards is still characterized by that of mechanical
typewriters. This paper presents a summary of a research project dealing with
the ergonomic improvement of keyboards, carried out at the IAO in Stuttgart
during the past five years. Extensive laboratory evaluation of experimental
keyboards, where different design parameters were tested under real life
conditions, have produced a relative optimum regarding ergonomic keyboard
design. An accompanying investigation of user acceptance evaluated all
realized parameters. In co-operation with a keyboard manufacturer, the results
were used to design a marketable product, which may be seen as an important
contribution to ergonomic keyboard design.

Observations, comments and results of short studies indicate that daily
production use of a mouse can lead to complaints of cramped hands from gripping
the case tightly, and stiff finger movements from operating the button(s), plus
soreness of the heel of the hand and wrist from rubbing on the work surface. A
series of short studies was conducted to develop and prove out design criteria
for a new mouse case design. Based on these results and a cost/performance
analysis based on marketing data, a decision was made to produce this mouse
design. These studies are briefly described along with the arguments used to
make the decision, and a description of the ergonomic tools and features
incorporated in this design are presented.

This paper describes a collaboration between industrial designers and
ergonomic specialists in developing a new input unit for two Scitex prepress
systems. Scitex prepress systems are operated with five input devices, most of
which are fixed in the workstation, forcing the operator into a rigid sitting
posture. A new portable input unit housing three of the input devices was
designed in an effort to improve the ergonomic features of the system. The
development entailed four states, each of which included the construction of a
working model, followed by experimentation and evaluation. Each stage
reinforced the positive features of the previous model while correcting its
faults. This process resulted in developing a comfortable, convenient-to-use,
efficient and attractive input unit.

A spoken dialogue between a user and a computer system has to be governed by
the system because of: (i) the limited capabilities of present word-recognition
apparatus; and (ii) the limited possibilities of the system for 'understanding'
its user. The user's part of the dialogue therefore needs to be unobtrusively
controlled by the system by carefully phrased and timed prompts. Short pauses
in these prompts enable the experienced user to make shortcuts through the
dialogue, without forsaking complete explanations for the inexperienced user.
The user is also able to control the system by utilizing other pauses in the
system utterances for corrective words or protests in case of incorrect
recognition.

Analyses of work demands, stress and strain were carried out at videotex
workplaces in the laboratory and in private households. The demand analysis
showed that a high degree of information resolution and accuracy during
information reception leads to high strain and eye fatigue. This effect is
increased by a heavy flicker of the CRT screen, an inadequate choice of colour
contrast, an inadequately low CRT resolution, and an inadequately small
distance between the worker and the screen. High demands in the field of
information processing are caused by the degree of difficulty in extracting
relevant information from the videotex system using the search trees. In
addition, the application of a checklist for CRT workplaces indicates more than
30 design faults. The analysis of the subjective perception of strain showed a
significant decrease of the motivation levels following videotex sessions, and
a significant increase of the strain level. The only individual factor to
increase during videotex sessions was self-confidence. A comparison with
findings of Udris and Barth (1976) showed that even videotex sessions which are
much shorter than an eight-hour working day result in strain reactions similar
to those occurring for eight hours of card-punching.

Inadequate Instruction in the Electronic Workplaces as a Cause of Mental
Strain

Mental strain is still a much debated health problem for people working in
the electronic workplace. Ergonomics and design help make offices
user-friendly, and physical strain can be prevented. A common reason for
mental strain is the lack of adequate instruction in the new technologies for
employees. An investigation based upon patient information shows the method of
instruction used, and recommendations are made as to which ones should be used.
The investigation also shows that environmental factors have to be taken into
consideration and that often side-effects have to be dealt with.

On the Design of Human-Computer Interaction for Administrative Offices

After pilot research in public sector administration offices of the FRG
state Baden-Wurttemberg, the registration and update of personnel data was
simulated in an experimental terminal station. The dialogue style was varied:
(a) Transaction-oriented: In this mode the data of a complete mask are sent
widespread to a host and checked there for input errors. The feedback is then
sent back to the terminal. (b) Field-oriented: In this mode the data of every
field or character is checked and feedback is sent back immediately. 25
administration officials participated in the trial sessions. They solved real
tasks (full case, update) with the different program versions. The
experimental data consisted of behaviour registration and interviews about
learning, working style and system features. From the results certain design
principles were formulated.

Modern office furniture is constructed in such a way that nobody is able to
use it correctly. Each day people sit for many hours hunched over their tables
in positions harmful to the back. The main reason for this seems to be the
low, backward sloping seats, which represent an effective hindrance to all
types of work over the table. This naturally leads to pronounced flexion and
strain of the back and neck. A higher, forward sloping seat will tend to
reduce the flexion and strain of the back and bring the person into a more
upright balanced position with a greater open angle between the body and the
thighs. This resembles the position taken when sitting on horseback. In an
experiment with data-entry personnel suffering from chronic back-pain furniture
was adjusted to a height which the subjects found most comfortable. On an
average they preferred to sit at a table 6.6 cm higher than recommended by
European Standardization (CEN). This higher position can only be used when
sitting on a forward sloping seat. The pain indication (Huskisson 1974) was
for the Standard furniture 67 mm compared to 35 mm on the higher furniture.
The flexion of the back was reduced from 75° to 64°. The evaluation
was made after a two month trial period.

With the introduction into the Dutch telecommunications service (PTT) of a
large number of visual display units and printers as a consequence of the
automation of a variety of applications, it became apparent that it was not
possible to compose desired workstation lay-outs with the furniture currently
in use, which, dated from the fifties; the need was apparent for a new, more
up-to-date furniture. Several anthropometric and field studies with regard to
the necessary adjustments and table-top shapes were performed. The results
indicated that the adjustments could be restricted to one: the height of the
table. The users considered shape and flexibility of the table-top very
important: it should be possible to create an optimal configuration for each
combination of VDU- and pen-and-paperwork. Market-research indicated that
state-of-the-art furniture did not meet PTT requirements. It was therefore
decided to design the table system in-house. However, because of logistical
problems it was decided to call in one of the major Dutch furniture
manufacturers for assistance, Gispen. The (almost complete) system is at
present commercially available as the Gispen ET ('Ergonomic Table') System.

The Steelcase Sensor chair was introduced in the spring of 1986. It is
designed to meet the special needs of modern office workers and their
technology by supporting and encouraging movements of the operator while
seated. The marketing and research trends that influenced the product
philosophy are discussed. The fifteen product criteria achieved in Sensor are
described, as are the pertinent ergonomic principles embodied in its design.

This research has been carried out in order to verify in the field the
exigencies yielded by a particular task and report indications for the
ergonomic optimization of the relevant workstation. The task under examination
was software design executed by 127 subjects in different environments. The
steps in which this research was carried out were as follows: analysis of the
task; analysis of subjects; analysis of the workstation and environment; and
observations on 24 subjects representative of the population. The observations
were in order to discover the level of posture variability and establish the
physical parameters to be optimized. Results show that, for the activity
examined, the heaviest restrictions imposed by the hardware refer to the
eye-screen distance, head movement and curvature of the trunk. Therefore, the
physical parameters to be optimized are height, width and depth of the table,
and height and design of the chair.

BIT 1987 Volume 6 Issue 4

Thirty advisory interactions between computer system 'help desk' consultants
and their clients were transcribed and analysed as part of a project to
determine the behavioural requirements for intelligent on-line help facilities.
An interesting property of these interactions is that the advice was frequently
modified in response to verification requests: questions (often syntactically
implicit) which contain presuppositional statements that are partial answers to
the asserted query. Designs for intelligent help facilities might exploit this
finding by supporting the verification strategy and attempting to extract and
use the presupposed statements in these questions to generate advice.

The aim of this study was to determine the degree of acceptance of synthetic
speech in a practical application and to clarify some of the factors which are
important for its acceptance. Synthetic speech was used in two simulated
telephone services. The availability of interrupt facilities, the speaking
rate and service type were varied. The performance (success in writing down
the requested data) and some subjective reactions were recorded. Performance
was worse with synthetic speech in comparison with normal speech. Neither the
interrupt facilities nor the speaking rate had any influence on performance.
The interrupt facilities were appreciated, although they were hardly used.
Having the possibility of interrupting the synthetic speech caused the subjects
to judge the system as more flexible and to rate the experienced tempo as
slower. The answers on the questions about acceptance suggested a positive
effect of the interrupt variable, but this was not significant. Suggestions
concerning the use of synthetic speech are given.

A search-and-select paradigm was adopted to investigate which visual
characteristics of icons are relevant for menu selection. Two icon sets
(abstract icons, representational icons) were compared to a word command set.
For abstract icons, global features were used in order to maximize their visual
distinctiveness. For representational icons local features were used in order
to ensure a high degree of representativeness and a small 'articulatory
distance'. Results revealed that abstract icons were searched and selected
much faster than both word commands and representational icons. In addition,
response time functions indicated that abstract icons can be searched in
parallel (no effect of menu size) whereas word commands and representational
icons have to be searched sequentially. Error rates were small in all
conditions, and there was no indication of a speed-accuracy tradeoff. Thus,
when icons are used in menu selection, visual distinctiveness (due to global
features) seems to override representativeness (due to local features).

A current bottleneck in the automation of cognitive tasks, such as software
development, is the lack of available, standardized, reliable and valid methods
for extracting knowledge from experts. This paper discusses the development of
Computer Aided Protocol (CAP) to automatically collect the general and specific
cognitive task components of subjects performing a programming task. The
effectiveness of CAP is evaluated in a statistically balanced experimental
design (n=30) by comparing it to traditional protocol analysis and a control
group. Results indicate that while neither treatment significantly altered the
solution process, CAP was able to collect the lower level commands while
protocol analysis collected only 56% of these lower level commands. However,
protocol analysis was able to obtain significantly more high level goals than
CAP. This work suggests that the integration of both protocol and CAP for
knowledge extraction would provide more effective information for the
development of expert systems than is feasible with either system alone.

A Psychological Study of Advance Manufacturing Technology: The Concept of
Coupling

The role played by technology as a discrete independent variable in shaping
the design of work is explored. The concept of coupling is developed and an
empirical study of work with advanced manufacturing technology (AMT), using
measurement scales derived from this concept, is outlined. Results indicate
that operators of tightly coupled AMT perceive stronger supervisory influence
on their working methods and show signs of lower intrinsic job satisfaction and
poorer mental health than operators of more loosely coupled AMT. Implications
for job redesign are discussed.

Introducing a Sales Order Processing System: The Importance of Human,
Organizational and Ergonomic Factors

This paper is a follow-up to an earlier study (Rowe 1985) and considers the
addition of a computerized sales order processing system at Barrington's food
factory. The earlier stock control system had not been without its problems,
and the lessons learned from this experience enabled management to avoid
repeating certain mistakes with regard to planning, office provision and
training. However, once in operation, the new system also experienced a number
of shortcomings, principally because management still overlooked important
human, organizational and ergonomic factors. As the previous article pointed
out, these factors are often less visible to management, and it resulted in
problems with regard to day-to-day operations, office reorganization, work
roles and inter-departmental communication. The concluding section advocates
the abandonment of 'technology-led system design' in favour of a more
evolutionary approach.

The Politics of the Quality of Worklife in Automated Offices in the USA

Rapid adoption of computer and communication equipment in the USA and the
changing nature of the US labour force led United States Congress, Office of
Technology Assessment to examine whether the current quality of worklife
policies and regulations were adequate. The policies for regulating the
quality of office worklife are part of a large socio-political regulatory
framework dating back to the United States Constitution. Current policy
debates about video display terminal health and safety must be considered in
terms of this broad regulatory landscape. Central to the debate is the nature
of the scientific evidence. Equally important is the ability of current labour
law to support user participation in the implementation process. The
discussion of office equipment and occupational standards in the USA addresses
the paucity and applicability of the existing scientific evidence, and the
question of who should develop standards.

Jacob et al. (1986) have discussed evidence of bias in the psychological
literature on human judgement and decision-making and considered some of the
implications for expert system design. The present paper comments upon (a) the
problems of interpreting the psychological evidence and (b) the influence of
prior knowledge and beliefs on human thought and judgement. The implications
for decision-making by computers, with or without the assistance of human
experts, are briefly discussed.